|
''Maiasaura'' (from the Greek "μαία" and the feminine form of Latin ''saurus'', meaning "good mother reptile") is a large herbivorous hadrosaurid ("duck-billed") dinosaur genus that lived in the area currently covered by the state of Montana in the Upper Cretaceous Period (mid to late Campanian), about 76.7 million years ago.〔Horner, J. R., Schmitt, J. G., Jackson, F., & Hanna, R. (2001). Bones and rocks of the Upper Cretaceous Two Medicine-Judith River clastic wedge complex, Montana. In Field trip guidebook, Society of Vertebrate Paleontology 61st Annual Meeting: Mesozoic and Cenozoic Paleontology in the Western Plains and Rocky Mountains. Museum of the Rockies Occasional Paper (Vol. 3, pp. 3-14).〕 The first fossils of ''Maiasaura'' were discovered in 1978. In 1979, the genus was named. The name refers to the find of nests with eggs, embryos and young animals, in a nesting colony. These showed that ''Maiasaura'' fed her young while they were in the nest, the first time such evidence was obtained for a dinosaur. Hundreds of bones of ''Maiasaura'' have been dug up. ''Maiasaura'' was about nine metres long. Young animals walked on their hind legs, adults on all fours. ''Maiasaura'' was probably closely related to ''Brachylophosaurus. ==Description== ''Maiasaura'' were large, attaining a maximum known length of about . They had a flat beak typical of hadrosaurids, and thick noses. They had a small, spiky crest in front of the eyes. This crest may have been used in headbutting contests between males during the breeding season.〔 ''Maiasaura'' were herbivorous. They were capable of walking both on two (bipedal) or four (quadrupedal) legs. Studies of the stress patterns of healed bones show that young juveniles under four years old walked mainly bipedal, switching to a mainly quadrupedal style of walking when they grew larger. They appeared to have no defense against predators, except, perhaps, its heavy muscular tail and their herd behavior. Herds were extremely large and could have comprised as many as 10,000 individuals.〔 ''Maiasaura'' lived in an inland habitat.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Maiasaura」の詳細全文を読む スポンサード リンク
|